I wanted to ask you a couple of questions.
What’s the difference between, ” After all ” and ” afterwards” ‘ For
example: “We are not good chefs, but after all, the food wasn’t that bad.”
“We had to study last night, but afterwards we went out for a few beers.”

‘Afterwards’ is a time expression. It refers to time.

‘After all’ is more than a time expression:

“I thought I was lost, but I was going the right way after all.”

“Let me help you. After all, you always help me.” (por lo menos)

“After all is said and done.” – al fin y al cabo, a fin de cuentas

“After all the trouble she’s caused me, I still love Berta.” (despues de
todo)

“We had lunch. Afterwards, John went home.”

¡OJO! It’s not correct to say, X”We had lunch. After, John went home.“X
– You should say, “We had lunch. After that, John went home.”